class Config:
    DEBUG = None
    #数据库链接
    SQLALCHEMY_DATABASE_URI = 'mysql://root:mysql@localhost/dier'
    #数据库动态追踪
    SQLALCHEMY_TRACK_MODIFICNTIONS = False
class developmentConfig(Config):
    DEBUG = True


class productionConfig(Config):
    DEBUG = False

config = {
    'development':developmentConfig,
    'production':productionConfig
}